Pipe-core and method of making the same.



G. W. MOWANE.

PIPE GORE AND METHOD OP MAKING THE SAME.

APPLICATION FILED JUNE 19, 1908.

Patented Dec. 15,1908.

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UNITED STATES PATENT OFFICE.

CHARLES W. MCWANE, OF LYNCHBURG, VIRGINIA, ASSIGNOR OF ONE-HALF TO HENRYE. MCWANE, OF LYNOIIBURG, VIRGINIA.

PIPE-CORE AND METHOD OF MAKING THE SAME.

Specification of Letters Patent.

Patented Dec. 15, 1908.

Application filed. June 19, 1908. Serial No. 439,366.

To all whom it may concern:

Be it known that I, CHARLES W. MGWANE, a citizen of the United States,residing at Lynchburg, in the county of Campbell and btate of Virginia,have invented a new and useful Pipe-Core and Method of Making the Same,of which the following is a specification.`

In casting iron pipes, particularly those of the larger sizes, the coresare expensive elements, requiring care and expertness in construction.In this connection, it must be remembered that during the castingoperation, and after the same is complete, the metal surrounding thecore is contracting as it cools, while the temperature of the core beingraised, is causing said core to expand. It

\ therefore becomes necessary to construct the core of material thatwill give7 or compress under this two-fold pressure. Yet thiscompression must be uniform at all points in order that there may be nodisplacement at any particular point or points, which would result in adefective casting. Of the various cores heretofore employed or proposed,the only commercially successful type up to the present time of which Iam aware, is that in which a perforated core barrel is employed that issurrounded by a layer of hay rope, the rope in turn being incased in aplurality of layers or coatings ofbaked loam or analogous material. Theexpense of this core is, however, very considera-ble. In the firstplace, the hay rope, which is burned out in the casting operation, iscostly and each coat has to be separately applied and separately baked,all of which requires considerable time before the core is ready foruse. Moreover the rope has to be wrapped upon the core barrel with greatcare and skill in order to avoid displacement Linder pressure or theresultant pipe may have its interior face transversely ribbed. Attemptshave been made to eliminate the rope by providing layers in whichcombustible material is incorporated, but in these structures, thevarious coatings are separately baked and produce a hard body notsufficiently compressible and very diflicult to remove from the finishedcasting.

Ihe primary object of the present invention is to provide a core that isvery inexpensive to manufacture both in point of time and material, willproduce as good if not better results than the cores now in general use,

and is readily removable from the finished pipe.

In the accompanying drawings Figure 1 is a cross sectional view of acore constructed in accordance with this invention. Fig. 2 is alongitudinal sectional view through a portion thereof.

Similar reference numerals designate corresponding parts in all thefigures of the drawings.

In this core, the usual barrel 3 is employed, which is preferablytubular in form, and is perforated, as shown at 4. This barrel ispreferably surrounded by a sheet 5 of holding material, such as cloth orperforated paper, but this sheet is not necessary, its particular objectbeing to provide a better surface than the metal for holding the innerlayer of material. This layer, which is designated 6, is formed of greensand which as is wellknown to those skilled in the art, is merelymolders sand dampened sufficiently to stick together. This coating isapplied either directly to the sheet 5, or if the sheet is not used,directly to the outer surface of the core barrel 3. As soon as thecoating' 6 is applied, an outer coating 7 of loam or other suitablematerial is applied, the coating 6 preferably not having been baked orotherwise treated before the application of the coating 7, though it maybe dried or baked without departing from the spirit of the invention.After the application of the outer coating 7, the mold is baked or driedin the usual manner, and is then ready for use. With this structuretherefore, the inner coating or layer 6 is incased by the outer hardenedcoating 7 the latter therefore constituting protecting and holding meansfor the green sand layer and providing a sufficiently firm support forthe molten iron. The inner layer 6 has sufficient compressibility tocompensate for the oppositely acting pressure due to the expanding coreand the contracting pipe. Furthermore it will be evident that the innerlayer 6 being dried, it will be in the form of a loose and granular masswhich will permit the ready removal of the barrel and the consequentWithdrawal of the core material from the finished pipe. Not only is thenecessity for hay rope obviated, but the core can be made in much lesstime as it requires but a single baking and therefore can be used thesame day as made, which is impracticable With those of the type aboveset forth. However as above stated, it is possible to bake, dry orpartially dry the green sand layer before applying the outer coat andthis additional step is in'- tended to be comprehended Within the scopeof the invention.

From the foregoing, it is thought that the construction, operation andmany advantages of the herein described invention Will be apparent tothose skilled in the art, Without further description, and it Will beunderstood that various changes in the size, shape, proportion, andminor details of construction, may be resorted to Without departing fromthe spirit or sacrificing any of the advantages of the invention.

I-Iaving thus fully described my invention, What I claim as new, anddesire to secure by Letters Patent, is

1. The method of 'producing a core for casting purposes, which consistsin placing a green sand coating on a core support, ap-

plying a protecting coating over the green sand coating, and drying thecore thus produced.

2. The method of producing a core for casting purposes, Which consistsin applying to a perforated core barrel a coating of green sand, dryingthe green sand coating, covering the green sand coating with a coatingof loam, 'and Vthen baking or 'drying the c ore thus produced.

3. A core for casting purposes, comprising an internal support, a greensand coating covering the same, and an external coating of hardenedmaterial incasing the green sand coating.

4L. A core for casting purposes, comprising a tubular core barrel havingperforated Walls, a green sand coating applied thereto, and a hardenedoutside coating of loam incasing the green sand core.

5. A core for casting purposes, comprising a tubular core barrel havingperforated Walls, a sheet of holding material wrapped upon its outerface, a green sand coating applied to the sheet, and a hardened outsidecoating incasing the green sand core.

6. The method of producing a core for casting purposes, Which consistsin applying to a perforated core barrel a coating of green sand,covering the green sand coating with a coating of loam, and then bakingor drying the core thus produced.

In testimony, that I claim the foregoing as my own, I have heretoaffixed my signature in the presence of two Witnesses.

CHARLES WV. MCVVANE.

Witnesses l JAMES E. MURPHY, JAMES C. BONDURANT.

